A phenomenological model of percolating magnetic nanostructures

Abstract:

Transport and magnetotransport properties were analysed systematically in percolating magnetic nanostructures such as Ni-rich NiFe-SiO₂and Fe-SiO₂ films. These granular magnetic films exhibit giant Hall effect. We identified features which are common and unique to these systems. Among the features are the correlation between a - log(T)-like temperature dependent resistivity and a particle size distribution having a large fraction of small nanometer sized particles, and the power law dependence between the magnetoresistivity and the room temperature resistivity. Assuming the presence of nanometer sized particles in the percolating conduction channels whose contributions are sensitive to temperature and the external magnetic field, we developed a phenomenological model to explain all the common features.